One way of doing it is to go into Display Property where you can ajust the Wallpaper, Screensaver, etc. Return to the Theme tab and select Save as... Next, put this custom .theme file in $OEM$\$$\Resources\Themes Also, add your background image in $OEM$\$$\Web\Wallpaper Next you'll add this to your Winnt.sif [Shell] CustomDefaultThemeFile="%WinDir%\Resources\Themes\xxx.theme"